The invention relates to a tool rack or storage for machine tools with numerical control for the machining of workpieces, particularly for single-spindle machine tools, for storing tools and for removing and returning the tools by means of a changing device or changer.
Tool racks of the foregoing type have a fixed, bottom-secured, vertical column, which carries a cylindrical, rotatably mounted rotor and which is equipped with a mounting means for the positive reception of the tools.
Tool racks are used in many machine tools, particularly for the machines with numerical control for machining of workpieces, especially in machining centers. Numerous different constructions of tool racks are known. One known basic construction of a tool rack is a disk-shaped plate magazine, on the circumference of which are arranged the tools, generally together with a tool holder. The tools are positioned in a drum-like or radial manner. In this radial arrangement of the tools, an increase in the number of storage locations can be obtained in that several such plate magazines can be arranged in layers one on top of another, as disclosed, for example, in German Patent No. 1,912,369. In this conventional rack, tools are mounted in axially displaceable blocks, with the aid of which the tools can be moved into a tool transfer position, where they can be removed from or returned to the magazine by the tool exchanger. However, relatively high expenditure for the displaceable mounting of the blocks and the displacement mechanism are disadvantageous.
Admittedly such expenditure can be reduced in that the tools can be arranged axially in several stages on a rotating drum and their longitudinal axis can be located tangentially to a circular path concentric to the cylinder, so that they can be removed and inserted by a gripping device. However, it is disadvantageous that only a relatively small number of tools can be arranged on the drum circumference, cf. Swiss Patent No. 556,712.
Another tool rack construction known is a chain magazine, in which tools are mounted parallel to each other or at right angles to the rotation axes of a rotating chain drive. However, if the number of tool locations in such a magazine is not adequate, it is necessary to set up a further magazine or magazines on the machine tool. A relatively large space requirement and relatively large expenditure for the control of the removal and return of the tools are, however, disadvantageous.
In addition, so-called flat racks are known, in which the tools are arranged on a planar, generally vertical surface and are removed from and returned to that surface by a portal loader. Thus, a large tool storage capacity can be achieved, and in addition each tool can be relatively rapidly reached by means of the portal loader, without it being necessary to move the entire tool mass, such as is e.g. the case with the plate or chain magazine. However, a disadvantage of the flat rack resides in the very large space requirement because, apart from its own space surface, each tool requires additional, unused access surfaces for the portal loader, so that the latter must move over considerable distances.
In another known construction of a tool rack of the present applicant (Swiss Patent Application No. 4344/86-BE 21 189), a cylindrical, rotatably mounted rotor is used, which is provided at its ends with circular running paths for receiving tool magazines provided with running gears, circumferentially displaceable relative to the motor and abutting against one another and which, accompanied by the formation of a magazine-free sector, are arranged for the loading and unloading of the rotor with tools and for the access of a handling means, e.g. a tool exchange loader. This construction ensures that the locations for the individual tools can be closely juxtaposed, but the magazine-free section is not available for occupancy by tools. Although this rack can be used for both single-spindle and multiple-spindle machine tools, its operation is directed more particularly at the latter.